1. Field of the Invention
The present invention relates to a vending machine. More particularly, it relates to a raw material sensing apparatus for a vending machine which can monitor whether or not raw materials for a user-selected article are output during vending.
2. Description of the Prior Art
A vending machine is a kind of a self-service stand generally holds packets of cigarettes, containers of coffee, other soft drinks, snacks, and books, so consumers can obtain them by putting coins into it. FIG. 1 depicts a conventional coffee vending machine. As shown in FIG. 1, the coffee vending machine includes a casing 1 which constitutes the outer appearance of the vending machine, and a door 2 that is hinged on one side of the front of casing 1 for opening and closing casing 2. On the outer surface of door 2 are formed a doorknob 3 used when opening and closing door 2, an article selection panel 5 with a plurality of selection keys used to choose a cup of user-desired coffee, a cup dispenser 6 providing a user with a cup of the selected coffee, and a coin reject slot 7 through which small change is output.
The internal structure of the conventional vending machine, as shown in FIG. 2, consists of a cup column 8 holding a plurality of paper cups; raw material receptacles 9 holding several kinds of coffee powder, cream, sugar, etc., for various kinds of coffee; raw material supply parts 10 through which raw materials are furnished to a mixing part 13; a raw material chute 11 installed under raw material supply parts 10, thus directing the flow of raw materials from raw material supply parts 10; a hot water supply part 12 furnishing hot water to mixing part 13; and mixing part 13 mixing the hot water from hot water supply part 12 with the raw materials for coffee, delivered through raw material chute 11, and outputting the same to cup dispenser 6 through nozzles.
The following description relates to the operation of the conventional coffee vending machine.
When a user puts a given amount of coins into the coffee vending machine through a coin slot 4 and then selects a type of coffee he or she wants manipulating article selection panel 5, a cup is supplied from cup column 8 and put in cup dispenser 6 according to an output signal of a control unit of the vending machine. Several raw materials for the selected coffee, output from raw material receptacles 9, are provided to mixing part 13 through raw material chute 11. Mixing part 13 mixes the raw materials in hot water, supplied from hot water supply part 12, and this mixture is provided to cup dispenser 6 through nozzles, in a manner that the coffee vending machine dispenses him or her with a cup of the desired coffee.
However, in case that each of powdered raw materials within the vending machine forms a hard mass by inside moisture, the vending machine dispenses customers with hot water that is not mixed with raw materials, thus causing a money loss to them.